1. Field of the Invention
This invention relates to the regulation of the discharge of an electrochemical battery. More particularly, the subject invention relates to circuitry which terminates the discharge of an electrochemical battery.
2. Description of Related Art
Drivers of vehicles and craft alike are frequently confronted with the problem of a dying or a dead battery. A dead battery is often a result of an accident, e.g., accidently leaving the lights on or leaving the interior dome light on. Additionally, the modern electronics found on newer automobiles can drain the battery to the point where it cannot start the engine.
One attempt to avoid this problem includes a battery housing actually containing two separate and distinct batteries. The battery used for everyday use comprises two-thirds of the housing volume. The smaller battery, which takes up the remaining one-third of the battery housing, is only used in emergencies by means of a manual switch, when the larger battery can no longer start the engine; the second battery being kept charged through an isolation diode. This solution to the problem of the stranded traveler is not ideal for two reasons. First, the everyday battery is only two-thirds the size of the battery specified by the vehicle manufacturer for the vehicle. Problems occur because of excessive drain on the battery and a lower available capacity. Insufficient power for on-board electronic components then begin to arise merely because the battery is too small for the particular application.
Second, the emergency battery is carried at all times and represents dead weight through most of the life of the battery. Additionally, the emergency battery must be switched over manually after emergency starting so that it may once again be charged by the vehicle charging system. Should the owner forget this step, the two batteries act as one and have no emergency back up utility.
A second solution to the problem of a dead battery is disclosed in U.S. Pat. No. 4,902,956 to Sloan, issued on Feb. 20, 1990. This invention comprises a circuit breaker which disconnects non-critical accessories when the charge on the battery drops below a predetermined level as measured by a voltmeter. An override switch allows the operator of the vehicle to reconnect the non-critical accessories. The circuit breaker receives a disabling signal when the engine is running so as not to disconnect the non-critical accessories during the operation of the vehicle.
This system does not, however, automatically alert the operator of the battery disconnection when the operator tries to start the vehicle. Nor does this invention disclose the capability of eliminating all current drains; drains created from such components as the starter and microprocessors which will eventually drain the battery even with the non-critical circuits disconnected.